a merged cell can't show the complete content

Steps to Reproduce

1. import the attached file with
2. check the merged cell at C10

Current Result

the 3rd line is not rendered

Expected Result

render the 3rd line

Debug Information

• 5.7.0 doesn't have this bug
• comparing to 5.7.0, there is overflow: hidden added at 5.8.0 that caused this problem
  .zscelltxt-wrap { word-wrap: break-word; width: inherit; overflow: hidden; }